A method has been devised to completely eliminate nerve cells from hydra. Our current investigations are indicating that nerve-free hydra can carry out all developmental processes (growth, regeneration, budding polarity maintenance, polarity reversal, induction and form regulation) typical of normal hydra. This seems to contradict other findings, with hydra and other animals including vertebrates, which show that nerves exert strong influences and controls over development. This apparent contradiction resembles that seen in vertebrate (amphibian) limbs, where nerves are absolutely required for regeneration: limb denervation abolishes regenerative capacities. Yet aneurogenic limbs (formed in denervated embryos) can regenerate in the absence of nerves. This suggests that nerves normally control development, but under some circumstances other cells can compensate for nerve cell absence. In this project we will determine a) to what extent epithelial cells in nerve-free hydra acquire new functions which compensate for the absence of nerve cells, b) which developmental controls are normally exerted by nerve cells and which are normally exerted by epithelial cells, and c) what factors govern the interplay between nerves and epithelial cells. These studies will involve elimination of hydra nerve cells using colchicine treatment, and repopulating the hydra with nerve cells of mutant hydra having abnormal development. Analysis of these chimeras will indicate which cell types control development. We will also determine whether or not epithelial cells have neurosecretory activity.